Mycoviruses infecting Colletotrichum spp.: A comprehensive review

Colletotrichum is one of the most economically important fungal genera, which affects a wide range of hosts, specifically tropical and subtropical crops. Thus far, there have been several records of mycovirus infection in Colletotrichum spp., primarily by viruses of the Partitiviridae family. There have also been records of infections by mycoviruses of the Chrysoviridae family. Mycoviruses are (+)ssRNA and dsRNA genome viruses, which may or may not be enveloped. To date, no mycovirus with a DNA genome has been isolated from Colletotrichum spp. Typically, mycoviruses cause latent infections, although hypo- and hypervirulence have also been reported in Colletotrichum spp. In addition to its effects on pathogenic behavior, mycovirus infection can lead to important physiological changes, such as altered morphological characteristics, reduced vegetative growth, and suppressed conidia production. Therefore, research on mycoviruses infecting phytopathogenic fungi can help develop alternative methods to chemical control, which can cause irreversible damage to humans and the environment. From an agricultural perspective, mycoviruses can contribute to sustainable agriculture as biological control agents via changes in fungal physiology, ultimately resulting in the total loss of or reduction in the virulence of these pathogens.

Efficacy of Beauveria bassiana and Beauveria pseudobassiana isolates against the pine processionary moth, Thaumetopoea wilkinsoni Tams, 1926 (Lepidoptera/Notodontidae)

Background The pine processionary moth, Thaumetopoea wilkinsoni Tams, 1926 (Lepidoptera/Notodontidae) is one of the most harmful insects that destroys pine ecosystems by feeding on pine leaves at its larval stage. Because of its urticating setae, the insect also causes severe skin reactions to animals and humans. Instead of chemical control, eco-friendly biological control methods are preferred to combat this species. Results The purpose of this study was to evaluate the efficacy of five different Beauveria bassiana Vuill, 1912 (Hypocreales/Cordycipitaceae) isolates (TR-SM-10, TR-SM-11, TR-SM-2, TR-SK-1 and TR-D-1) and one B. pseudobassiana Rehner & Humber (Hypocreales/Cordycipitaceae) isolate (TR-SM-1) against the fourth instar larvae of T. wilkinsoni under laboratory conditions. T. wilkinsoni larvae were collected from the Ondokuz Mayıs University Kurupelit Campus in Samsun, Turkey, in 2021, and the fourth instar larvae were used in the experiment. Two ml of spray of the six fungal isolates were applied to every ten larvae at each concentration (1 × 107 and 1 × 108 conidia ml−1). The experiment was carried out in five replicates per group, and the larvae were observed for 10 days. As a result, all isolates of B. bassiana caused 100% mortality at 1 × 108 conidia ml−1 concentration. B. pseudobassiana isolate also caused 100% mortality at both concentrations. At 1 × 107 conidia ml−1 concentration, the larvae treated with the B. pseudobassiana isolate (TR-SM-1) had the lowest LT50 (2.89 days) and LT90 values (4.79 days), while the larvae treated with TR-SM-10 isolate had the highest LT50 (5.65 days) and LT90 values (9.39 days). At 1 × 108 conidia ml−1 concentration, the larvae treated with TR-SK-1 isolate had the lowest LT50 (2.89 days) and LT90 values (4.79 days), while those treated with TR-SM-10 isolate had the highest LT50 (3.95 days) and LT90 values (8.15 days). Conclusion It has been recommended that the five different isolates of B. bassiana and B. pseudobassiana isolates were virulent to T. wilkinsoni larvae and can be used for biological control of T. wilkinsoni.

Hoeing as a Possibility for Mechanical Weed Control in Winter Oilseed Rape (Brassica napus L.)

The framework conditions for chemical weed control in oilseed rape (OSR) are becoming increasingly unfavorable in Central Europe. On the one hand, weed resistance is spreading and, on the other, there is a growing social desire to reduce or eliminate the use of chemical crop protection products. In a field experiment, hoeing, as a weed control measure performed two times per growing season (one time in autumn and one time in spring) in oilseed rape (Brassica napus; two varieties), was compared to chemical control by herbicides and a combination of hoeing and herbicide application (five treatments altogether). The chemical control by herbicides consisted of a broad-spectrum pre-emergence treatment and a post-emergence graminicide application. The trial was set up in each of three periods (years 2014/2015, 2015/2016, and 2016/2017) at the experimental station Ihinger Hof, University of Hohenheim, Stuttgart, Germany. The effect of the treatments on weed plant density, weed biomass at the time of harvesting, and on OSR grain yield was investigated. Weed plant density was measured four times per trial year, each time before and after hoeing. In 2015/2016 after spring hoeing, and in 2016/2017 at all data collection times, weed plant density was significantly higher in hoeing without herbicide application than in the other variants. No significant differences occurred at the other data collection times. The weed plant density ranged from 0.5 to 57.8 plants m−2. Regardless of the trial year, pure hoeing always resulted in a significantly higher weed biomass at the time of harvesting than the herbicide applications or the combinations. The weed biomass at the time of harvesting ranged between 0.1 and 54.7 g m−2. No significant differences in grain yield between hoeing and herbicide application occurred in all three trial years. According to the results, hoeing is a suitable extension of existing integrated weed control strategies in OSR.

Application of oxyfluorfen and pendimethalin to control weeds on soybean plantation

The appearance of weeds on crops has led to the significant loss of crop yield. Therefore, chemical control with herbicides has been an important tool for rapid and efficient weed management in crops. The objective of this study was to evaluate the effect of herbicides oxyfluorfen and pendimethalin against weeds on soybean plantation. This research employed Randomized Completely Block Design (RCBD) Factorial with 2 factors. The first factor was the type of herbicides: oxyfluorfen and pendimethalin. The second factor was herbicide doses: 0, 500, 1000, 1500 and 2000 g a.i ha-1, applied on soybean at 1 day after planting (DAP). The percentage of weed control, percentage of weed coverage, weed species, weed population, and weed dry weight were observed at 3, 5, 7 and 9 weeks after planting (WAP). The results revealed that different types and doses of herbicide applied has affected the percentage of weed control, percentage of weed coverage weed species and weed dry weight.

Biocontrol of Rice Diseases by Microorganisms

Rice is responsible for the stable crop of 3 billion people worldwide, about half of Asian depends on it, and rice is grown in more than 100 countries. Rice diseases can lead to devastating economic loss by decreasing yield production, disturbing a stable food supply and demand chain. The most commonly used method to control rice disease is chemical control. However, misuse of chemical control can cause environmental pollution, residual toxicity, and the emergence of chemical-resistant pathogens, the deterioration of soil quality, and the destruction of biodiversity. In order to control rice diseases, research on alternative biocontrol is actively pursued including microorganism-oriented biocontrol agents. Microbial agents control plant disease through competition with and antibiotic effects and parasitism against plant pathogens. Microorganisms isolated from the rice rhizosphere are studied comprehensively as biocontrol agents against rice pathogens. Bacillus sp., Pseudomonas sp., and Trichoderma sp. were reported to control rice diseases, such as blast, sheath blight, bacterial leaf blight, brown spot, and bakanae diseases. Here we reviewed the microorganisms that are studied as biocontrol agents against rice diseases.

CHEMICAL CONTROL OF PEACHES FROM CLASTEROSPORIOSIS IN THE CONDITIONS OF THE REPUBLIC OF UZBEKISTAN

Peach varieties Istikbol and Gulnoz were found to be resistant to clasterosporiosis. The incidence rate ranged from 13.0 to 45.0%, with the severity of the disease from 8.0 to 22.7%. In the fight against clasterosporiosis, the chemical method is considered the most effective. For chemical protection, it is recommended early spring triple treatment of trees in the following terms: 1 - before the buds swell; 2 - after blooming of trees; 3 - two weeks after blooming, with one of the following fungicides: Skor 250 EC (normally 0.02% suspension), Kresoxin 50% WDG. (0.02%), Topsin-M 70% WP (0.1%) and Falcon 46% EC (0.05%) against peach clasterosporiosis. KEYWORDS: peach, fungus, disease, clasterosporiosis, fungicide, efficiency, productivity

CHEMICAL CONTROL OF HELMINTHOSPORIUM LEAF SPOT OF PERENNIAL RYEGRASS

The results of experiments to determine the effectiveness of the Bravo fungicide in the fight against Helminthosporium leaf spot are presented. It was found that early spring spraying of perennial ryegrass with Bravo at a dose of 1.5 l/ ha reduced the development of the disease by 5 times compared to the control.

A Comparative Study of Fluoride Containing Chlorhexidine and Non Chlorhexidine Mouthrinses in a Teenage Group

Background: Mouthwashes are important means used in chemical control of dental plaque. There is strong evidence suggestive of better effectiveness, when fluoride is added to chlorhexidine mouthwash. Objectives: The study was planned to assess the effect of a mouthrinse containing Chlorhexidine (CHX) and amine/stannous fluoride (AmF) on plaque accumulation, gingivitis and salivary fluoride levels in comparison with two mouthrinses containing either essential oils (EO) or cetylpyridinium chloride (CPC) with sodium fluoride (NaF) in a teenage group. Methodology: For this study 90 healthy teenage between 12 and 20 years were recruited for participation. The experimental gingivitis model consisted of a 2-weeks recruitment phase, followed by a 6-day rinsing period with one of the 4 mouthrinse formulations was used for the study. At the end of the pre-phase period and the rinsing period (Day-0/Day-6), gingival index (GI), plaque index (PI) and salivary fluoride levels were recorded. The statistical analyses were performed using Wilcoxon sign test and the dependent t test. Results: A reduction in plaque re-growth was seen for the CHX+AmF formulation rinse, although there were no significant differences among all groups (p>0,001). During the experimental periods, the gingivitis indices increased significantly for all formulations (p<0,001), except for the CHX+AmF formulation. The CHX+AmF formulation scored higher levels of salivary fluoride at the end of the rinsing period (p>0,001). Conclusion: We would like to conclude that the adjunctive use of AmF containing CHX mouthrinses to mechanical oral hygiene should be recommended for teenage at risk groups. Keywords: CT KUB, Radiation safety, Minimise radiation